Display apparatus and method of manufacturing the same

ABSTRACT

A display apparatus includes: a substrate; a display unit disposed on the substrate; a barrier unit disposed between the substrate and the display unit; and a buffer unit disposed between the barrier unit and the display unit, wherein a sum of a thickness of the barrier unit and a thickness of the buffer unit is in the range from 0.9 μm to 3 μm.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2014-0072006, filed on Jun. 13, 2014, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein in its entirety by reference.

BACKGROUND

1. Field

Aspects of embodiments of the present invention relate to a displayapparatus and a method of manufacturing the display apparatus.

2. Description of the Related Art

Recently, display apparatuses have been used for various purposes. Also,as the thickness and weight of these apparatuses have been reduced, theapplication range thereof has expanded.

In particular, thin and portable display apparatuses have been recentlymanufactured.

A display apparatus includes a display unit for realizing images. Ifimpurities, humidity, or external air enters the display unit, anoperation error or a defect of the display unit may occur.

In particular, if the display apparatus is of a thin type, impurities,humidity, and external air that enter the display unit may severelydegrade the characteristics of the display device.

SUMMARY

One or more embodiments of the present invention include a displayapparatus and a method of manufacturing the display apparatus.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments of the present invention, a displayapparatus includes: a substrate; a display unit disposed on thesubstrate; a barrier unit disposed between the substrate and the displayunit; and a buffer unit disposed between the barrier unit and thedisplay unit, wherein a sum of a thickness of the barrier unit and athickness of the buffer unit is in the range from 0.9 μm to 3 μm.

The barrier unit and the buffer unit each may include an inorganicmaterial.

The barrier unit may include an oxide material or a nitride material.

The barrier unit may include a structure in which an oxide material anda nitride material are stacked.

The barrier unit may include a first barrier unit including siliconoxide and a second barrier layer including silicon nitride, and whereinthe first barrier layer is between the second barrier layer and thesubstrate.

The buffer unit may include an oxide material or a nitride material.

The buffer unit may include a structure in which an oxide material and anitride material are stacked.

The buffer unit may include a first buffer layer including siliconnitride and a second buffer layer including silicon oxide, and whereinthe first buffer layer is between the second buffer layer and thesubstrate.

An uppermost layer of the buffer unit may contact the display unit andwherein the uppermost layer may include a flat surface.

The substrate may include an organic material.

The substrate may include polyimide, polyethylene naphthalate,polyethylene terephthalate (PET), polyarylate, polycarbonate,polyetherimide (PEI), or polyethersulfone.

The substrate may include a first layer including an organic material, asecond layer including an organic material, and an insulating insertionlayer disposed between the first layer of the substrate and the secondlayer of the substrate and including an inorganic material.

The insulating insertion layer may include an oxide material or anitride material.

The display apparatus may further include a protective layer on asurface of the substrate opposite a surface of the substrate facing thebarrier unit.

The display unit may include an organic light emitting device.

The display unit may further include at least one thin film transistor(TFT).

The display apparatus may further include an encapsulation member on thedisplay unit.

According to one or more embodiments of the present invention, a methodof manufacturing a display apparatus, the method includes: forming abarrier unit on a substrate; forming a buffer unit on the barrier unit;and forming a display unit on the buffer unit, wherein the forming ofthe barrier unit and the forming of the buffer unit are performed sothat a sum of a thickness of the barrier unit and a thickness of thebuffer unit is in the range from 0.9 μm to 3 μm.

The method may further include, before the forming of the display unit,preparing a carrier unit for supporting the substrate and disposing thesubstrate on the carrier unit.

The carrier unit may be removed before manufacturing of the displayapparatus is completed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view of a display apparatusaccording to an embodiment of the present invention;

FIGS. 2A and 2B are diagrams of modified embodiments of the displayapparatus of FIG. 1 further including an encapsulation member;

FIG. 3 is an enlarged view of a portion A of FIG. 1;

FIG. 4 is a graph showing a variation in characteristics of a displayapparatus according to a variation in a sum of a thickness of a barrierunit and a thickness of a buffer unit of FIG. 3;

FIG. 5 is an enlarged view of a portion K of FIG. 1;

FIGS. 6 and 7 are diagrams showing modified embodiments of the portion Kin FIG. 1;

FIG. 8 is a schematic cross-sectional view of a display apparatusaccording to another embodiment of the present invention;

FIG. 9 is an enlarged view of a portion B in FIG. 8; and

FIGS. 10A, 10B, 10C, and 10D are schematic diagrams illustrating amethod of manufacturing a display apparatus according to an embodimentof the present invention.

DETAILED DESCRIPTION

As aspects of the present invention allow for various changes andnumerous embodiments, particular embodiments will be illustrated in thedrawings and described in detail in the written description. However,this is not intended to limit the present invention to particular modesof practice, and it is to be appreciated that all changes, equivalents,and substitutes that do not depart from the spirit and technical scopeof the present invention are encompassed in the present invention.

Hereinafter, aspects of the present invention will be described indetail by explaining preferred embodiments of the invention withreference to the attached drawings. Like reference numerals in thedrawings denote like elements.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

As used herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

It will be understood that when a layer, region, or component isreferred to as being “formed on” another layer, region, or component, itcan be directly or indirectly formed on the other layer, region, orcomponent. For example, intervening layers, regions, or components maybe present.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, because sizes and thicknesses of componentsin the drawings are arbitrarily illustrated for convenience ofexplanation, the following embodiments are not limited thereto.

In the following examples, the x-axis, the y-axis, and the z-axis arenot limited to three axes of the rectangular coordinate system, and maybe interpreted in a broader sense. For example, the x-axis, the y-axis,and the z-axis may be perpendicular to one another, or may representdifferent directions that are not perpendicular to one another.

When a certain embodiment may be implemented differently than aspresented, a specific process order may be performed differently fromthe described order. For example, two consecutively described processesmay be performed substantially at the same time (e.g., concurrently) orperformed in an order opposite to the described order. Expressions suchas “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist.

FIG. 1 is a schematic cross-sectional view of a display apparatus 100according to an embodiment of the present invention, and FIG. 3 is anenlarged view of a portion A of FIG. 1.

Referring to FIGS. 1, 2A, 2B, and 3, the display apparatus 100 accordingto the one includes a substrate 101, a display unit D, a buffer unit120, and a barrier unit 110.

The buffer unit 120 and the barrier unit 110 are disposed between thesubstrate 101 and the display unit D.

In FIG. 1, an additional member is not disposed on the display unit D ofthe display apparatus 100. However, embodiments of the present inventionare not limited thereto.

For example, as shown in FIGS. 2A and 2B, one or more encapsulationmembers 191 and 192 may be further formed on the display unit D.

FIGS. 2A and 2B are diagrams showing modified examples of the displayapparatus 100 of FIG. 1 further including an encapsulation member.

In particular, FIG. 2A shows a display apparatus 100′ in which anencapsulation member 191, for example, a thin film encapsulation layer,is formed on the display unit D. The encapsulation member 191 may beformed of various insulating materials, for example, an organic materialor an inorganic material, and may have a structure in which one or moreorganic materials and one or more inorganic materials are stacked.

Also, FIG. 2B shows a display apparatus 100″ in which an encapsulationmember 192 of a substrate type is disposed on (or over) the display unitD to face the substrate 101. A sealing member SE is disposed between thesubstrate 101 and the encapsulation member 192 so as to couple thesubstrate 101 and the encapsulation member 192 to each other.

The modified examples shown in FIGS. 2A and 2B are selected embodimentsof the present invention, and aspects of the present invention mayinclude other various embodiments in addition to the above modifiedexamples.

The components of the display apparatus 100 according to one embodimentwill be described below.

The substrate 101 may be formed of various materials. In particular, thesubstrate 101 may be formed of a flexible material according to oneembodiment, or, according to another embodiment, the substrate 101 maybe formed of an organic material. For example, the substrate 101 maycontain an organic material having excellent heat resistance anddurability such as polyimide, polyethylene naphthalate, polyethyleneterephthalate (PET), polyarylate, polycarbonate, polyetherimide (PEI),or polyethersulfone.

The barrier unit 110 and the buffer unit 120 are sequentially formed onthe substrate 101. In particular, the barrier unit 110 is formed betweenthe substrate 101 and the display unit D, and the buffer unit 120 isformed between the barrier unit 110 and the display unit D.

In one embodiment of the present invention, a protective layer 102 maybe further formed on a surface of the substrate 101, which is opposite asurface facing the barrier unit 110 and the buffer unit 120. Theprotective layer 102 may block impurities, humidity, or external airfrom entering a lower portion of the substrate 101, and may alsomitigate or prevent deformation of the substrate 101.

The barrier unit 110 is formed on a surface of the substrate 101. Thebarrier unit 110 may include various insulating materials, and may beformed in various ways.

The barrier unit 110 may provide a planarization layer on an uppersurface of the substrate 101, and may impede or prevent infiltration ofimpurities and humidity into the display unit D from the substrate 101.

The barrier unit 110 may include an inorganic insulating layer, forexample, silicon oxide or silicon nitride.

In an embodiment, the barrier unit 110 includes a first barrier layer111 and a second barrier layer 112. The second barrier layer 112 isformed on the first barrier layer 111. For example, the second barrierlayer 112 is disposed farther from the substrate 101 than the firstbarrier layer 111 (e.g., the first barrier layer 111 is between thesecond barrier layer 112 and the substrate 101).

Also, in one embodiment of the present invention, the first barrierlayer 111 includes silicon oxide, for example, SiOx, and the secondbarrier layer 112 includes silicon nitride, for example, SiNx.

For example, by forming the first barrier layer 111 adjacent to thesubstrate 101 and forming the first barrier layer 111 by using siliconoxide, an interfacial bonding property between the first barrier layer111 and the substrate 101 may be improved. Also, if the second barrierlayer 112 includes silicon nitride and a first buffer layer 121 (thatwill be described later) in the buffer unit 120 includes siliconnitride, an interfacial bonding property between the first barrier layer111 and the substrate 101 may be improved. Also, if the second barrierlayer 112 includes silicon nitride and the first buffer layer 121 (thatwill be described later) in the buffer unit 120 includes siliconnitride, an interfacial bonding property between the second barrierlayer 112 and the first buffer layer 121 may be improved.

The buffer unit 120 is formed on the barrier unit 110. The buffer unit120 may include various insulating materials, and may be formed on thebarrier unit 110 in various ways.

The buffer unit 120 may operate as a planarization layer on an uppersurface of the substrate 101, and impedes or prevents infiltration ofimpurities or humidity into the display unit D from the substrate 101.In particular, because the display unit D is formed on the buffer unit120, the uppermost surface of the buffer layer 120, for example, asecond buffer layer 122 of the buffer unit 120 may include a flatsurface.

The buffer unit 120 may include an inorganic insulating layer including,for example, silicon oxide or silicon nitride.

In an embodiment of the present invention, the buffer unit 120 includesthe first buffer layer 121 and the second buffer layer 122. The firstbuffer layer 121 is formed on the barrier unit 110, and the secondbuffer layer 122 is formed on the first buffer layer 121. For example,the second buffer layer 122 may be disposed farther from the substrate101 than the first buffer layer 121 is.

Also, the first buffer layer 121 may include silicon nitride, forexample, SiNx, and the second buffer layer 122 may include siliconoxide, for example, SiOx.

In particular, in one embodiment the second buffer layer 122 is formedadjacent to the display unit D, and the second buffer layer 122containing silicon oxide, and then, interfacial bonding property betweenthe display unit D and the buffer unit 120 may be improved. Also, if thesecond barrier layer 112 includes silicon nitride and the first bufferlayer 121 is includes silicon nitride, the interfacial bonding propertybetween the second barrier layer 112 and the first buffer layer 121 maybe improved.

Also, the display unit may include a thin film transistor (TFT), and theTFT includes an active layer 303. The active layer 303 may be formed ofa silicon material. In this case, the interfacial bonding propertybetween the active layer 303 including silicon and the second bufferlayer 122 including silicon oxide may be improved, and thus, electricalproperties of the TFT may be improved.

Also, if the first buffer layer 121 includes silicon nitride, hydrogenmay be included in silicon nitride, and thus, the mobility of carriersin the active layer 303 of the TFT may be improved provided that thedisplay unit D formed on the buffer unit 120 includes the TFT.Accordingly, electrical properties of the TFT may be improved.

A sum of a thickness T1 of the barrier unit 110 and a thickness T2 ofthe buffer unit 120 may range from 0.9 μm to 3 μm.

If a crack is generated or a generated crack starts spreading in thebarrier unit 110 and the buffer unit 120 having a total thickness of 0.9μm, impurities, foreign substances, external air in the substrate 101,or gas remaining after the forming of the substrate 101 may betransferred to the display unit D via the crack in the barrier unit 110and the buffer unit 120. In this case, the image quality characteristicsof the display unit D are degraded, and a defect may occur in thedisplay unit D.

According to one embodiment, the sum of the thickness T1 of the barrierunit 110 and the thickness T2 of the buffer unit 120 is set to begreater than or equal to 0.9 μm (9000 Å).

FIG. 4 is a graph showing variation in characteristics of the displayapparatus according to a change in the sum of the thickness T1 of thebarrier unit 110 and the thickness T2 of the buffer unit 120 in FIG. 3.

In FIG. 4, line (or graph) A denotes a defect generation rate of thedisplay unit according to the change in the sum of the thickness T1 ofthe barrier unit 110 and the thickness T2 of the buffer unit 120, andline (or graph) B denotes a reciprocal number of a stiffness of thebarrier unit 110/the buffer unit 120 according to the change in the sumof the thickness T1 of the barrier unit 110 and the thickness T2 of thebuffer unit 120.

In particular, an X-axis in the graph of FIG. 4 denotes the sum of thethickness T1 of the barrier unit 110 and the thickness T2 of the bufferunit 120, and is represented in a unit of angstroms (Å). A Y-axis in thegraph of FIG. 4 denotes a defect generating rate (left side) of thedisplay apparatus and a reciprocal number (right side) of the stiffnessof the barrier unit 110/buffer unit 120.

The stiffness is proportional to Young's modulus and a cube of thethickness. For example, the stiffness of the barrier unit 110 and thebuffer unit 120 is proportional to a cube of the sum of the thickness T1of the barrier unit 110 and the thickness T2 of the buffer unit 120.

Referring to FIG. 4, the line B depicting the reciprocal number of thestiffness of the barrier unit 110 and the buffer unit 120 has a curvedshape that is similar to the defect generating rate of the displayapparatus. For example, the reciprocal number of the stiffness of thebarrier unit 110 and the buffer unit 120 is proportional to the defectgenerating rate of the display apparatus. Thus, if the stiffness of thebarrier unit 110 and the buffer unit 120 increases, the defectgenerating rate of the display apparatus is reduced.

In particular, when the sum of the thickness T1 of the barrier unit 110and the thickness T2 of the buffer unit 120 increases, the reciprocalnumber of the stiffness of the barrier unit 110 and the buffer unit 120is reduced. For example, the stiffness of the barrier unit 110 and thebuffer unit 120 increases. Also, when the sum of the thickness T1 of thebarrier unit 110 and the thickness T2 of the buffer unit 120 increases,the defect generating rate of the display apparatus is reduced.

In particular, if the sum of the thickness T1 of the barrier unit 110and the thickness T2 of the buffer unit 120 is greater than or equal to0.9 μm (9000 Å), the defect generating rate of the display apparatus isreduced to 1% or less.

Therefore, the sum of the thickness T1 of the barrier unit 110 and thethickness T2 of the buffer unit 120 is set to be greater than or equalto 0.9 μm so as to effectively impede or prevent humidity or impuritiesfrom infiltrating into the barrier unit 110 and the buffer unit 120.Also, by setting the sum of the thickness T1 of the barrier unit 110 andthe thickness T2 of the buffer unit 120 to be greater than or equal to0.9 μm, the spread of a crack that may be generated in the display unitD or the substrate 101 to the barrier unit 110 and the buffer unit 120may be mitigated or prevented. Also, generation of a crack in thebarrier unit 110 and the buffer unit 120 may be mitigated or prevented.

Also, if the sum of the thickness T1 of the barrier unit 110 and thethickness T2 of the buffer unit 120 is increased from 0.8 μm to 0.9 μm,the defect generating rate is reduced from about 2% to about 1%. On theother hand, if the sum of the thickness T1 of the barrier unit 110 andthe thickness T2 of the buffer unit 120 is increased from 0.9 μm to 1μm, the defect generating rate is reduced from about 1% to about 0.9%,that is, the defect generating rate barely changes. Therefore, in orderto effectively reduce the defect generating rate by increasing thethickness T1 of the barrier unit 110 and the thickness T2 of the bufferunit 120, the sum of the thickness T1 of the barrier unit 110 and thethickness T2 of the buffer unit 120 is set to be equal to at least 0.9μm.

According to some embodiments of the present invention, the sum of thethickness T1 of the barrier unit 110 and the thickness T2 of the bufferunit 120 is set to be equal to 3 μm or less so that flexibility of thesubstrate 101 may be maintained even when the barrier unit 110 and thebuffer unit 120 are used, thereby realizing a display apparatus 100 thatis flexible.

If the sum of the thickness T1 of the barrier unit 110 and the thicknessT2 of the buffer unit 120 exceeds 3 μm, efficiency of processes formanufacturing the barrier unit 110 and the buffer unit 120 is degraded,and flexibility of the display apparatus 100 is reduced. Thus, user'sconvenience and characteristics in manufacturing processes may bedegraded.

In an embodiment of the present invention, the first barrier layer 111of the barrier unit 110 may have a thickness of 5000 Å, the secondbarrier layer 112 may have a thickness of 600 Å, the first buffer layer121 of the buffer unit 120 may have a thickness of 500 Å, and the secondbuffer layer 122 may have a thickness of 4000 Å.

The display unit D is formed on the buffer unit 120. According to anembodiment, an insertion buffer layer may be further disposed betweenthe display unit D and the buffer unit 120 for mitigating or preventingthe infiltration of impurities and operating as a planarization layer.The display unit D will be described below with reference to FIGS. 5, 6,and 7.

FIG. 5 is an enlarged view of a portion K in FIG. 1, and FIGS. 6 and 7show modified examples of the portion K in FIG. 1.

Referring to FIG. 5, an organic light-emitting device 130 is formed onthe substrate 101, in particular, on the buffer unit 120 and the barrierunit 110 that are formed on the substrate 101.

The organic light-emitting device 130 includes a first electrode 131, asecond electrode 132, and an intermediate layer 133.

The first electrode 131 is formed on the buffer unit 120. The firstelectrode 131 may be formed of various conductive materials. Accordingto one embodiment of the present invention, the first electrode 131 mayinclude indium tin oxide (ITO), indium zinc oxide (IZO), ZnO, or In₂O₃.Also, according to another embodiment, the first electrode 131 mayinclude a reflective layer formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir,Cr, Li, Yb, or Ca.

The intermediate layer 133 is formed on the first electrode 131. Theintermediate layer 133 includes an organic emission layer for emittingvisible light. The intermediate layer 133 may be a low molecular weightor a high molecular weight organic layer. Also, the intermediate layer133 includes the organic emission layer, and may additionally includeone or more selected from a hole injection layer (HIL), a hole transportlayer (HTL), an electron transport layer (ETL), and an electroninjection layer (EIL).

The second electrode 132 may be formed on the intermediate layer 133.The second electrode 132 may be formed of various conductive materials,for example, metals such as Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li,or Ca.

FIG. 6 is a cross-sectional view showing a modified example of theportion K in FIG. 1.

Referring to FIG. 6, an organic light-emitting device 230 is formed onthe substrate 101, and in particular, on the buffer unit 120 and thebarrier unit 110 formed on the substrate 101.

Only differences from the above embodiment will be described below forthe sake of convenience.

A first electrode 231 is formed on the buffer unit 120.

The first electrode 231 may be formed of various conductive materials. Apixel defining layer 219 is formed of an insulating layer on the firstelectrode 231. The pixel defining layer 219 has an opening so as toexpose an upper surface of the first electrode 231.

The intermediate layer 233 is formed on the exposed upper surface of thefirst electrode 231. The intermediate layer 233 includes an organicemission layer that emits visible light.

A second electrode 232 is formed on the intermediate layer 233.

FIG. 7 is a cross-sectional view showing another modified example of theportion K in FIG. 1.

Referring to FIG. 7, an organic light-emitting device 330 and a TFT areformed on the substrate 101, and in particular, on the buffer unit 120and the barrier unit 110 formed on the substrate 101.

The organic light-emitting device 330 includes a first electrode 331, asecond electrode 332, and an intermediate layer 333.

The TFT includes an active layer 303, a gate electrode 305, a sourceelectrode 307, and a drain electrode 308.

The active layer 303 is disposed on an upper surface of the buffer unit120 as a pattern (e.g., a predetermined pattern). The active layer 303may include an inorganic semiconductor material such as silicon, anorganic semiconductor material, or an oxide semiconductor material, andmay be formed by injecting p-type or n-type dopants.

A gate insulating layer 304 is formed on the active layer 303. The gateelectrode 305 is formed on the gate insulating layer 304 to correspondto (or in a location corresponding to or aligned with) the active layer303.

An interlayer insulating layer 306 is formed to cover the gate electrode305, and the source electrode 307 and the drain electrode 308 are formedon the interlayer insulating layer 306 to contact regions (e.g.,predetermined regions) of the active layer 303.

A passivation layer 318 is formed to cover the source electrode 307 andthe drain electrode 308, and an additional insulating layer may befurther formed on the passivation layer 318 to planarize the TFT.

The first electrode 331 is formed on the passivation layer 318. Thefirst electrode 331 is formed to be electrically connected to one of thesource electrode 307 and the drain electrode 308 (e.g., the firstelectrode 331 is electrically connected to the source electrode 307 orthe drain electrode 308).

In addition, the pixel defining layer 319 is formed on the firstelectrode 331. The pixel defining layer 319 is formed so as not to coverat least an area (e.g., a predetermined area) on the upper surface ofthe first electrode 331. The intermediate layer 333 including theorganic emission layer is formed on the upper surface of the firstelectrode 331. The second electrode 332 is formed on the intermediatelayer 333.

In one embodiment, the display unit D includes the organiclight-emitting device 130, 230, or 330; however, embodiments of thepresent invention may include various kinds of display unit D. Forexample, the display unit D may include various types of display devicessuch as a liquid crystal display (LCD) device.

According to one embodiment, when manufacturing the display apparatus,the barrier unit 110 and the buffer unit 120 are formed on the substrate101. Also, the sum of the thickness T1 of the barrier unit 110 and thethickness T2 of the buffer unit 120 may range from 0.9 μm to 3 μm.

As such, a crack that may be generated in the display unit D or thesubstrate 101 may not spread to the barrier unit 110 and the buffer unit120.

In addition, by setting the sum of the thickness T1 of the barrier unit110 and the thickness T2 of the buffer unit 120 to be equal to 3 μm orless, the flexibility of the substrate 101 may be maintained when thesubstrate 101 is used together with the barrier unit 110 and the bufferunit 120. Therefore, the display apparatus 100 that is flexible may bemanufactured.

Thus, the durability of the display apparatus 100 may be improved,generation of defects may be mitigated or prevented, and the flexibilitymay be improved. Thus, the display apparatus 100 may be manufactured tohave improved user convenience.

FIG. 8 is a cross-sectional view of a display apparatus 200 according toanother embodiment of the present invention, and FIG. 9 is an enlargedview of a portion B of FIG. 8.

Referring to FIGS. 8 and 9, the display apparatus 200 of one embodimentincludes the display unit D, a buffer unit 220, and a barrier unit 210.The encapsulation member 191 or 192 shown in FIGS. 2A and 2B may be usedin the embodiments of the display apparatus 200.

Also, the display unit D may have the structure shown in FIG. 5, 6, or7, and may include other various display devices.

For the sake of convenience, differences from the above embodiment willbe described below.

The barrier unit 210 and the buffer unit 220 are sequentially formed ona substrate 201.

In one embodiment, a protective layer 202 may be further formed on asurface of the substrate 201 opposite a surface facing the barrier unit210 and the buffer unit 220. The protective layer 202 may protectagainst or block impurities, humidity, or external air that may beintroduced through a lower portion of the substrate 201, and may alsomitigate or prevent deformation of the substrate 201.

The protective layer 202 may include various insulating materials, andmay be formed on a surface of the substrate 201 in various ways. Forexample, the protective layer 202 of a film type may be formed on thesurface of the substrate 201.

The substrate 201 may include a first layer 201 a, a second layer 201 b,and an insertion insulating layer 201 c. In one embodiment, theinsertion insulating layer 201 c is disposed between the first layer 201a and the second layer 201 b. The first layer 201 a is closer to thebarrier unit 210 than the second layer 201 b is.

The first layer 201 a and the second layer 201 b may be formed ofvarious materials. For example, the first layer 201 a and the secondlayer 201 b may be formed of a flexible material. According to oneembodiment, the first layer 201 a and the second layer 201 b may beformed of an organic material. For example, the first layer 201 a andthe second layer 201 b may include an organic material having excellentheat resistance and durability such as polyimide, polyethylenenaphthalate, PET, polyarylate, polycarbonate, PEI, or polyethersulfone.

The insertion insulating layer 201 c may be formed of various insulatingmaterials. According to one embodiment, the insertion insulating layer201 c includes an oxide material or a nitride material, for example, asilicon oxide such as SiO₂.

The barrier unit 210 is formed on a surface of the substrate 201. Thebarrier unit 210 may include various insulating materials, and may beformed on the surface of the substrate 201 in various ways.

The barrier unit 210 operates as a planarization surface on an uppersurface of the substrate 201, and may impede or prevent impurities andhumidity from infiltrating into the display unit D from the substrate201.

The barrier unit 210 may include an inorganic insulating layer, forexample, silicon oxide or silicon nitride.

In one embodiment of the present invention, the barrier unit 210includes a first barrier layer 211 and a second barrier layer 212. Thesecond barrier 212 is formed on the first barrier layer 211. Forexample, the second barrier layer 212 is disposed farther from thesubstrate 201 than the first barrier 211 is.

Also, in an embodiment of the present invention, the first barrier layer211 may include a silicon oxide, for example, SiOx. The second barrierlayer 212 may include a silicon nitride, for example, SiNx.

In particular, the first barrier layer 211 is formed to be adjacent tothe substrate 201, and the first barrier layer 211 includes siliconoxide so as to improve the interfacial bonding property between thefirst barrier layer 211 and the substrate 201. Also, if the secondbarrier layer 212 includes silicon nitride and a first buffer layer 221that will be described later in the buffer layer 220 includes siliconnitride, the interfacial bonding property between the second barrierlayer 212 and the first buffer layer 221 may be improved.

The buffer unit 220 is formed on the barrier unit 210. The buffer unit220 may include various insulating materials, and may be formed on asurface of the barrier unit 210 in various ways.

The buffer unit 220 may operate as a planarization layer on the uppersurface of the substrate 201, and may impede or prevent impurities andhumidity from infiltrating into the display unit D from the substrate201. In particular, because the display unit D is formed on the bufferunit 220, an uppermost surface of the buffer unit 220, for example, asecond buffer layer 222 of the buffer unit 220 (that will be describedlater), may operate as a planarization layer.

The buffer unit 220 includes an inorganic insulating layer, for example,silicon oxide or silicon nitride.

As an embodiment of the present invention, the buffer unit 220 includesthe first buffer layer 221 and the second buffer layer 222. The firstbuffer layer 221 is formed on the barrier unit 210, and the secondbuffer layer 222 is formed on the first buffer layer 221. For example,the second buffer layer 222 is disposed farther from the substrate 201than the first buffer layer 221.

Also, the first buffer layer 221 may include a silicon nitride, forexample, SiNx. The second buffer layer 222 may include a silicon oxide,for example, SiOx.

In particular, the second buffer layer 222 may be formed to be adjacentto the display unit D and the second buffer layer 222 may includesilicon oxide so as to improve an interfacial bonding property betweenthe display unit D and the buffer unit 220. Also, if the second barrierlayer 212 includes silicon nitride and the first buffer layer 221includes silicon nitride, the interfacial bonding property between thesecond barrier layer 212 and the first buffer layer 221 may be improved.

Also, the display unit D may include a TFT as described above, and theTFT includes an active layer 303 that may include a silicon material. Inthis case, an interfacial bonding property between the active layer 303including silicon nitride and the second buffer layer 222 includingsilicon nitride is improved, and thus, the electrical properties of theTFT may be improved.

In addition, if the first buffer layer 221 includes silicon nitride, thesilicon nitride may include hydrogen. As such, a mobility of carriers inthe active layer 303 of the TFT may be improved provided that thedisplay unit D formed on the buffer unit 220 includes the TFT.Accordingly, the electrical properties of the TFT may be improved.

A sum of a thickness T1 of the barrier unit 210 and a thickness T2 ofthe buffer unit 220 may range from 0.9 μm to 3 μm.

By setting the sum of the thickness T1 of the barrier unit 210 and thethickness T2 of the buffer unit 220 to be greater than or equal to 0.9μm, infiltration of humidity or impurities into the barrier unit 210 andthe buffer unit 220 may be effectively mitigated or prevented. Also, bysetting the sum of the thickness T1 of the barrier unit and thethickness T2 of the buffer unit 220 to be greater than or equal to 0.9μm, spreading of a crack generated in the display unit D or thesubstrate 201 to the barrier unit 210 or the buffer unit 220 may bemitigated or prevented. In addition, generation of the crack in thebarrier unit 210 or the buffer unit 220 may be mitigated or prevented.

If a crack is generated or a generated crack starts spreading in thebarrier unit 210 and the buffer unit 220, impurities, foreignsubstances, external air in the substrate 201, or gas remaining afterforming the substrate 201 may be transferred to the display unit D viathe crack generated in the barrier unit 210 and the buffer unit 220. Inone embodiment, the above problem may be reduced by forming the sum ofthe thickness T1 of the barrier unit 210 and the thickness T2 of thebuffer unit 220 to be greater than or equal to 0.9 μm.

For example, if the sum of the thickness of the barrier unit 210 and thebuffer unit 220 is less than 0.9 μm, stiffness of the barrier unit 210and the buffer unit 220 is reduced, and then, the barrier unit 210 andthe buffer unit 220 may bend easily. Thus, a crack may be generated or acrack generated in the display unit D may be easily transferred.Therefore, according to some embodiments of the present invention, thesum of the thickness of the barrier unit 210 and the buffer unit 220 isgreater than or equal to 0.9 μm.

In addition, the sum of the thickness of the barrier unit 210 and thebuffer unit 220 is set to be equal to 3 μm or less, and thus flexibilityof the substrate 201 may be maintained when the barrier unit 210 and thebuffer unit 220 are used together with the substrate 201, therebyrealizing the display apparatus 200 that is flexible.

If the sum of the thickness of the barrier unit 210 and the buffer unit220 exceeds 3 μm, the efficiency of processes for manufacturing thebarrier unit 210 and the buffer unit 220 is degraded, and theflexibility of the display apparatus 200 is reduced. Therefore, user'sconvenience and manufacturing process characteristics are degraded.

In one embodiment, the first barrier layer 211 of the barrier unit 210has a thickness of 5000 Å, the second barrier layer 212 has a thicknessof 600 Å, the first buffer layer 221 of the buffer unit 220 has athickness of 500 Å, and the second buffer layer 222 has a thickness of4000 Å.

The display apparatus 200 of one embodiment includes the first layer 201a, the second layer 201 b, and the insertion insulating layer 201 c, andthus, the substrate 201 may have excellent durability.

In particular, in the display apparatus 200 according to one embodiment,the substrate 201 has a structure in which the first layer 201 and thesecond layer 201 b are sequentially stacked. Thus, impurities, externalair, and foreign substances that may be introduced through the substrate201 may be easily blocked or impeded. Thus, generation of a crack in thesubstrate 201 or transfer of a crack to the display unit D via thesubstrate 201 may be mitigated or prevented.

Also, because the insertion insulating layer 201 c is disposed betweenthe first layer 201 a and the second substrate 201 b, a coupling powerbetween the first layer 201 a and the second layer 201 b may beimproved. In addition, the insertion insulating layer 201 c maysecondarily impede or block the impurities or external air that may passthrough the first layer 201 a or the second layer 201 b so as to improvedurability and image quality characteristics of the display apparatus200.

In addition, like the display apparatus 100 of the previous embodiment,the generation of crack or transferring of the crack may be mitigated orprevented so as to improve the durability of the display apparatus 200that may be formed to be flexible.

FIGS. 10A, 10B, 10C, and 10D are schematic diagrams illustrating amethod of manufacturing a display apparatus according to an embodimentof the present invention.

In detail, FIGS. 10A through 10D illustrate processes of manufacturingthe display apparatus 100′ of FIG. 2A. However, embodiments of thepresent invention are not limited thereto, and processes may be used tomanufacture also the display apparatus shown in FIG. 1, 2B, or 7.

Referring to FIG. 10A, the substrate 101 may be disposed on a carrierunit CU. The carrier unit CU may be formed of various materials, forexample, a material having a strength that is greater than that of thesubstrate 101. For example, the carrier unit CU may be formed of a glassmaterial. The carrier unit CU may allow easy handling of the substrate101 of a thin film type during the manufacturing processes of thedisplay apparatus 100′. For example, reduction in a processing accuracycaused by bending of the substrate 101 may be mitigated or prevented,and damage and deformation of the substrate 101 may also be mitigated orprevented, thereby improving the quality of the display apparatus 100′.

In particular, if the substrate 101 is formed of a flexible material,for example, if the display apparatus 100′ that is manufactured isflexible, convenience in manufacturing processes may be improved.

Referring to FIG. 10B, the display unit D is formed on the upper surfaceof the substrate 101, for example, a surface of the substrate 101opposite the surface facing the carrier unit CU. Although not shown inFIG. 10B, the buffer unit and the barrier unit are formed between thesubstrate 101 and the display unit D.

After that, referring to FIG. 10C, an encapsulation member 191 of anencapsulation layer type is formed on the display unit D. Theencapsulation member 191 may be formed of various insulating materials,for example, an organic material or an inorganic material. Theencapsulation member 191 may have a structure in which one or moreorganic layers and one or more inorganic layers are stacked.

Also, an encapsulation member 192 of a substrate type may be disposed onthe display unit D to face the substrate 101 as shown in FIG. 2B, and asealing member SE may be disposed between the substrate 101 and theencapsulation member 192 so that the substrate 101 and the encapsulationmember 192 are coupled to each other by the sealing member SE.

Referring to FIG. 10D, the carrier unit CU is removed to finish themanufacturing of the display apparatus 100′. If the carrier unit CU isremoved after forming the display unit D and the encapsulation member191, the display apparatus as shown in FIGS. 2A and 2B may bemanufactured.

According to the manufacturing method of one embodiment, when thedisplay apparatus 100′ is manufactured by using the carrier unit CU, thesubstrate 101 may be easily handled.

In particular, if the substrate 101 is formed of a flexible material,for example, if the display apparatus 100′ that is manufactured isflexible, the convenience in the manufacturing processes may beimproved.

As described above, according to the one or more of the aboveembodiments of the present invention, the durability of the displayapparatus and user's convenience may be improved.

It should be understood that the exemplary embodiments described thereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments of the present invention have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope of thepresent invention as defined by the following claims and equivalentsthereof.

What is claimed is:
 1. A display apparatus comprising: a substrate; adisplay unit disposed on the substrate; a barrier unit disposed betweenthe substrate and the display unit; and a buffer unit disposed betweenthe barrier unit and the display unit, wherein a sum of a thickness ofthe barrier unit and a thickness of the buffer unit is in a range from0.9 μm to 3 μm, and wherein the substrate comprises polyimide,polyethylene naphthalate, polyethylene terephthalate (PET), polyarylate,polycarbonate, polyetherimide (PEI), or polyethersulfone, wherein thebuffer unit comprises a first layer comprising silicon nitride, whereinthe barrier unit comprises a second layer comprising silicon nitride,and wherein the first layer contacts the second layer.
 2. The displayapparatus of claim 1, wherein the barrier unit and the buffer unit eachcomprise an inorganic material.
 3. The display apparatus of claim 1,wherein the barrier unit comprises an oxide material or a nitridematerial.
 4. The display apparatus of claim 1, wherein the barrier unithas a structure in which an oxide material and a nitride material arestacked.
 5. The display apparatus of claim 1, wherein the barrier unitcomprises a first barrier layer comprising silicon oxide and a secondbarrier layer comprising silicon nitride, and wherein the first barrierlayer is between the second barrier layer and the substrate.
 6. Thedisplay apparatus of claim 1, wherein the buffer unit comprises an oxidematerial or a nitride material.
 7. The display apparatus of claim 1,wherein an uppermost layer of the buffer unit contacts the display unitand wherein the uppermost layer comprises a flat surface.
 8. The displayapparatus of claim 1, wherein the substrate comprises an organicmaterial.
 9. The display apparatus of claim 1, wherein the substratecomprises a first layer including an organic material, a second layerincluding an organic material, and an insulating insertion layerdisposed between the first layer of the substrate and the second layerof the substrate and including an inorganic material.
 10. The displayapparatus of claim 9, wherein the insulating insertion layer comprisesan oxide material or a nitride material.
 11. The display apparatus ofclaim 1, further comprising a protective layer on a surface of thesubstrate opposite a surface of the substrate facing the barrier unit.12. The display apparatus of claim 1, wherein the display unit comprisesan organic light emitting device.
 13. The display apparatus of claim 1,wherein the display unit further comprises at least one thin filmtransistor (TFT).
 14. The display apparatus of claim 1, furthercomprising an encapsulation member on the display unit.
 15. A displayapparatus comprising: a substrate; a display unit disposed on thesubstrate; a barrier unit disposed between the substrate and the displayunit; and a buffer unit disposed between the barrier unit and thedisplay unit, wherein a sum of a thickness of the barrier unit and athickness of the buffer unit is in a range from 0.9 μm to 3 μm, whereinthe substrate comprises polyimide, polyethylene naphthalate,polyethylene terephthalate (PET), polyarylate, polycarbonate,polyetherimide (PEI), or polyethersulfone, and wherein the buffer unitcomprises a structure in which an oxide material and a nitride materialare stacked.
 16. A display apparatus comprising: a substrate; a displayunit disposed on the substrate; a barrier unit disposed between thesubstrate and the display unit; and a buffer unit disposed between thebarrier unit and the display unit, wherein a sum of a thickness of thebarrier unit and a thickness of the buffer unit is in a range from 0.9μm to 3 μm, wherein the substrate comprises polyimide, polyethylenenaphthalate, polyethylene terephthalate (PET), polyarylate,polycarbonate, polyetherimide (PEI), or polyethersulfone, wherein thebuffer unit comprises a first buffer layer comprising silicon nitrideand a second buffer layer comprising silicon oxide, and wherein thefirst buffer layer is between the second buffer layer and the substrate.